KR20160001584A - Flexible organic light emitting display panel and method of driving the same - Google Patents

Abstract

The present invention is to provide a flexible organic light emitting display panel including a buffer formed with bottom shield metal (BSM), and a manufacturing method thereof. To achieve the purpose, the flexible organic light emitting display panel according to the present invention comprises: a lower substrate; a buffer formed on the lower substrate; a switching transistor which includes a first active insulated from first lower protection metal constituting the buffer and overlapped with the first lower protection metal, is formed on the buffer, and is driven according to a first scan signal supplied along a gate line formed on the lower substrate; a driving transistor which includes a second active insulated from second lower protection metal constituting the buffer and overlapped with the second lower protection metal, is formed on the buffer, and is driven according to a data voltage supplied by the transistor from a data line formed on the lower substrate; a flat film formed on the switching transistor and the driving transistor; and an organic light emitting diode which is formed on the flat film and is connected with a first electrode of the driving transistor.

Description

TECHNICAL FIELD [0001] The present invention relates to a flexible organic light emitting display panel and a method of manufacturing the same. [0002] FLEXIBLE ORGANIC LIGHT EMITTING DISPLAY PANEL AND METHOD OF DRIVING THE SAME [

The present invention relates to an organic light emitting display panel and a method of manufacturing the same, and more particularly, to a flexible organic light emitting display panel including a thin film transistor formed on a plastic substrate and a method of manufacturing the same.

Recently, with the development of the information society, the importance of flat panel display devices (FPDs) having excellent characteristics such as thinning, light weight, and low power consumption is increasing. Examples of the flat panel display include a liquid crystal display (LCD), a plasma display panel (PDP), and an organic light emitting display (OLED). Recently, Electrophoretic display devices (EPD) are also widely used.

Among them, liquid crystal display devices and organic light emitting display devices including thin film transistors are excellent in resolution, color display, image quality, and are widely commercialized as display devices for televisions, notebooks, tablet computers, or desktop computers.

Particularly, the organic light emitting diode (OLED) uses a self-luminous element, has low power consumption, has a high response speed, a high luminous display rate, a high luminance and a wide viewing angle and is attracting attention as a next generation flat panel display .

Currently, glass substrates, quartz substrates, and the like are widely used in flat panel display devices. However, the above-described substrate has the disadvantage that it is liable to be cracked and heavy. Therefore, glass substrates, quartz substrates, and the like are not suitable for the manufacture of flexible flat panel display devices. Therefore, in order to manufacture a flexible flat panel display device, a method of forming a thin film transistor on a flexible substrate, typically a flexible plastic film, has been attempted.

1 is a circuit diagram illustrating a pixel structure of a conventional flexible organic light emitting display panel.

A pixel P of a conventional organic light emitting display panel includes an organic light emitting diode (OLED), a switching transistor Tsw, a driving transistor Tdr, and a capacitor Cst, as shown in FIG. 1, the switching transistor Tsw and the driving transistor Tdr are implemented as an N-type MOS-FET. However, the switching transistor Tsw and the driving transistor Tdr are not limited thereto and may be implemented as a P-type MOS-FET.

The switching transistor Tsw is turned on according to a scan pulse SP supplied to the scan line SL so that the data voltage Vdata transmitted from the data line DL is supplied to the gate of the drive transistor Tdr To the storage capacitor Cst.

The driving transistor Tdr is switched according to the data voltage Vdata supplied from the switching transistor Tsw to control the current Ioled flowing to the organic light emitting diode OLED by the first voltage EVdd.

The capacitor Cst is connected between a gate of the driving transistor Tdr and a first electrode (for example, a source) and supplies a voltage Vdata corresponding to a data voltage Vdata supplied to the gate of the driving transistor Tdr And the driving transistor Tdr is turned on by the stored voltage.

The organic light emitting diode OLED is electrically connected between a first electrode (e.g., a source) of the driving transistor Tdr and a second voltage (EVss) supply terminal, And emits light by the supplied current Ioled.

2 is a cross-sectional view of one pixel applied to a conventional flexible organic light emitting display panel.

In a conventional flexible organic light emitting display panel, as shown in Fig. 2, a lower substrate 10 made of plastic is attached on an auxiliary substrate A An organic light emitting diode E connected to the driving transistor Tdr is formed on the lower substrate 10. The auxiliary substrate (A) is composed of a glass substrate (80) and a sacrifice layer (85). The auxiliary substrate A is separated from the lower substrate 10 on which the organic light emitting diode E is formed through a laser-releasing process.

However, in the conventional flexible organic light emitting display panel, the active layer 23 of the driving transistor Tdr formed on the lower substrate 10 by the laser irradiated in the process of separating the auxiliary substrate A and the lower substrate 10 May be damaged.

In addition, in the conventional flexible organic light emitting display panel, the threshold voltage Vth of the driving transistor Tdr is fluctuated due to a back channel phenomenon generated by the first substrate 10 and the sacrifice layer 85 .

In other words, in the conventional flexible organic light emitting display panel, the active of various transistors including the driving transistor Tdr may be damaged by the laser. In addition, a negative charge trap is generated in the sacrificial layer due to the laser and light incident from the outside, so that charges in the polyimide (PI) forming the lower substrate 10 And moves toward the sacrifice layer 85, thereby increasing the potential of the surface of the polyimide (PI) 10. Accordingly, the threshold voltage Vth of the transistors is shifted in a positive direction.

In addition, the conventional flexible organic light emitting display device is not shown in the drawings, but may be exposed to light in a module process and a post-production management process. At this time, the device characteristics of the driving transistor may be varied.

The shift of the threshold voltage as described above lowers the reliability of the thin film transistor and the organic light emitting display panel.

Such reliability degradation of the thin film transistor and the organic light emitting display panel can also be generated in the switching transistor Tsw.

The present invention provides a flexible organic light emitting display panel including a buffer having a bottom shield metal (BSM) formed thereon and a method of manufacturing the same.

According to an aspect of the present invention, there is provided a flexible OLED display panel including: a lower substrate; A buffer formed on the lower substrate; And a second active protective film formed on the buffer, the first active protective film being insulated from a first lower protective metal constituting the buffer and overlapping with the first lower protective metal, A switching transistor driven according to a scan signal; And a second active layer which is insulated from a second lower protective metal constituting the buffer and overlaps with the second lower protective metal, and is formed in the buffer, and from the data line formed on the lower substrate, A driving transistor driven according to a data voltage supplied through the driving transistor; A flat film formed on the switching transistor and the driving transistor; And an organic light emitting diode formed on the flat film and having a first electrode connected to a first driving electrode of the driving transistor.

According to another aspect of the present invention, there is provided a flexible organic light emitting display panel including: a lower substrate; A buffer formed on the lower substrate; A transistor formed in the buffer, the buffer being insulated from a lower protective metal constituting the buffer and being superimposed on the lower protective metal; A flat film formed on the transistor; And an organic light emitting diode formed on the flat film and driven by the transistor to output light, the transistor including a first gate terminal and a second gate terminal separated from the one gate connection line, , The active includes a first active terminal overlapping the first gate terminal and a second active terminal overlapping the second gate terminal, the first active terminal and the second active terminal being connected to each other , The lower protective metal is superposed only on either the first active terminal or the second active terminal.

According to another aspect of the present invention, there is provided a method of fabricating a flexible OLED display panel, including: forming a buffer on a lower substrate including a first lower protective metal and a second lower protective metal; A switching transistor including a first lower protective metal and a first active on the buffer, the switching transistor being insulated from the first lower protective metal and overlapping the first lower protective metal, Forming a driving transistor including a second active; Forming a flat film on top of the switching transistor and the driving transistor; And forming an organic light emitting diode having a first electrode electrically connected to a first driving electrode of the driving transistor driven according to a data voltage supplied through the switching transistor on the flat film.

According to another aspect of the present invention, there is provided a method of fabricating a flexible organic light emitting display panel, including: forming a buffer including a lower protective metal on a lower substrate; Forming a transistor on the buffer, the transistor being insulated from the lower protection metal and being active with the lower protection metal; Forming a planar film on top of the transistor; And forming an organic light emitting diode on the flat film, the organic light emitting diode being driven by the transistor and outputting light, wherein the step of forming the transistor comprises the steps of: Stacking a second active terminal; Covering the first active terminal and the second active terminal with a gate insulating film; And forming a gate in the gate insulating film, the gate having a first gate terminal and a second gate terminal overlapping the first active terminal and the second active terminal, wherein the lower protective metal comprises: Terminal or the second active terminal.

According to an aspect of the present invention, there is provided a flexible organic light emitting display panel including a buffer having a bottom shield metal (BSM) formed thereon, The active damage of the thin film transistor formed on the lower substrate by the laser can be prevented.

In addition, according to the present invention, it is possible to prevent the threshold voltage of the driving transistor from shifting due to a back channel phenomenon caused by the lower substrate and the sacrificial layer.

In addition, in the present invention, it is possible to prevent the device characteristics of the thin film transistor from fluctuating due to light, which is introduced in the management process after the module process and the product manufacture.

Further, the present invention can prevent the shift of the threshold voltage and improve the reliability of the thin film transistor and the display panel.

1 is a circuit diagram for explaining a pixel structure of a conventional flexible organic light emitting display panel.
2 is a cross-sectional view of one pixel applied to a conventional flexible organic light emitting display panel.
FIG. 3 is an exemplary view for explaining a flexible organic light emitting display panel according to the present invention. FIG.
4 is a circuit diagram illustrating a pixel structure of a flexible organic light emitting display panel according to the present invention.
5A is a cross-sectional view illustrating a driving transistor of one pixel of a flexible organic light emitting display panel according to the first embodiment of the present invention.
5B is a cross-sectional view illustrating a switching transistor of one pixel of a flexible organic light emitting display panel according to the present invention.
6 is a cross-sectional view illustrating a driving transistor of one pixel of a flexible organic light emitting display panel according to a second embodiment of the present invention.
7 is a cross-sectional view illustrating a driving transistor of one pixel of a flexible organic light emitting display panel according to a third embodiment of the present invention.
8A to 8E are various cross-sectional views for explaining a method of manufacturing a flexible organic light emitting display panel according to the present invention.
FIGS. 9A to 9C are views showing a transistor applied to a flexible organic light emitting display panel according to the present invention.

Hereinafter, an organic light emitting display panel and a method of manufacturing the same according to embodiments of the present invention will be described with reference to the accompanying drawings.

3 is an exemplary view for explaining a flexible organic light emitting display panel according to the present invention.

3, the flexible organic light emitting display according to the present invention includes pixels 110 formed at intersections of gate lines GL1 to GLg and data lines DL1 to DLd A gate driver 200 for sequentially supplying scan pulses to the gate lines GL1 to GLg formed on the panel 100, A data driver 300 for supplying a data voltage to the lines DL1 to DLd and a timing controller 400 for controlling the functions of the gate driver 200 and the data driver 300. [

In the panel 100, a pixel P 110 is formed in an area where a plurality of gate lines GL and a plurality of data lines DL intersect each other.

Each pixel 110 includes an organic light emitting diode for outputting light and a pixel driver for driving the organic light emitting diode.

First, the organic light emitting diode may be configured as a top emission type in which light generated from the organic light emitting diode is emitted to the outside through an upper substrate. However, (Bottom Emission) mode.

Secondly, the pixel driver includes at least two transistors and a storage capacitor connected to the data line DL and the gate line GL to control driving of the organic light emitting diode OLED .

The anode of the organic light emitting diode (OLED) is connected to the first power source, and the cathode is connected to the second power source. The organic light emitting diode OLED outputs light having a predetermined luminance corresponding to the current supplied from the driving transistor.

The driving unit controls the amount of current supplied to the organic light emitting diode OLED according to a data voltage supplied to the data line DL when a scan pulse is supplied to the gate line GL.

To this end, the driving transistor is connected between the first power source and the organic light emitting diode, and the switching transistor is connected between the driving transistor and the data line DL and the gate line GL.

Next, the timing controller 400 generates a gate control signal GCS for controlling the gate driver 200 by using a vertical synchronizing signal, a horizontal synchronizing signal and a clock supplied from an external system (not shown) And outputs a data control signal DCS for controlling the data driver 300.

The timing controller 400 samples the input image data input from the external system, rearranges the input image data, and supplies the rearranged digital image data to the data driver 300.

That is, the timing controller 400 rearranges the input image data supplied from the external system to transmit the rearranged digital image data to the data driver 300, and supplies the clock supplied from the external system, A gate control signal GCS for controlling the gate driver 200 and a data enable signal for controlling the data driver 300 and the data driver 300, respectively, using a clock signal, a vertical synchronization signal (the clock and the signals are simply referred to as a timing signal) And transmits the data control signal DCS to the gate driver 200 and the data driver 300.

In particular, in order to achieve the above-mentioned object, the timing controller 400 includes a receiver for receiving the input image data and various signals as described above from the external system, An image data processor for rearranging the image data according to the panel to generate the rearranged digital image data, a controller for controlling the gate driver 200 and the data driver 300 using signals received from the receiver A control signal generation unit for generating the gate control signal GCS and the data control signals DCS and a control signal generation unit for generating the control signal based on the image data and the control signals generated by the data driving unit 300 or the gate driving unit And a transmitting unit for outputting the data to the mobile station 200.

Next, the data driver 300 converts the image data inputted from the timing controller 400 into an analog data voltage, and supplies a data voltage of one horizontal line in each horizontal period in which the scan pulse is supplied to the gate line To the data lines. That is, the data driver 300 converts the image data into a data voltage using the gamma voltages supplied from the gamma voltage generator (not shown), and outputs the data voltage to the data lines.

That is, the data driver 300 generates a sampling signal by shifting a source start pulse (SSP) from the timing controller 400 according to a source shift clock (SSC). The data driver 300 latches the image data input according to the source shift clock SSC according to a sampling signal, changes the data to a data voltage, and then outputs the source output enable (SOE) And supplies the data voltage to the data lines in units of horizontal lines in response to a signal.

The gate driver 200 sequentially supplies scan pulses to the gate lines GL1 to GLg of the panel 100 in response to the gate control signal input from the timing controller 400. [ Accordingly, the switching transistors formed in the respective pixels of the corresponding horizontal line to which the scan pulse is input are turned on, so that an image can be output to each pixel 110.

That is, the gate driver 200 shifts a gate start pulse (GSP) transmitted from the timing controller 400 according to a gate shift clock (GSC) On voltage to scan lines GL1 to GLg. The gate driver 200 supplies a gate-off voltage to the gate lines GL1 to GLn during the remaining period during which the scan pulse is not supplied.

The gate driver 200 may be formed to be independent from the panel 100 and may be electrically connected to the panel 100 in various ways, Panel (Gate In Panel: GIP) method. In this case, the gate control signal for controlling the gate driver 200 may be a start signal VST and a gate clock GCLK.

Although the data driver 300, the gate driver 200 and the timing controller 400 are independently configured in the above description, the data driver 300 or the gate driver 200 Either one of them may be integrally formed in the timing controller 400. Hereinafter, the gate driver 200, the data driver 300, and the timing controller 400 are collectively referred to as a panel driver.

4 is a circuit diagram for explaining a pixel structure of a flexible organic light emitting display panel according to the present invention.

4, the pixel P includes an organic light emitting diode (OLED), a driving transistor Tdr, a switching transistor Tsw, a sensing transistor Tss, an emission transistor Tem, capacitors C1 and C2, . Each of the transistors Tdr, Tsw, Tss and Tem is an N-type thin film transistor (TFT), and may be an a-Si TFT, a poly-Si TFT, an oxide TFT, .

The organic light emitting diode OLED is connected between a first driving power supply line PL1 to which a first voltage Vdd is supplied and a second driving power supply line PL2 to which a second voltage Vss is supplied. The organic light emitting diode (OLED) includes an anode, a cathode, and an organic layer formed therebetween. The anode is connected to the first electrode (e.g., the source electrode) of the driving transistor. The organic layer may include a hole transport layer, an organic emission layer, an electron transport layer, a hole injection layer, and an electron injection layer.

The organic light emitting diode OLED emits light with brightness corresponding to the amount of current flowing from the first driving power supply line PL1 to the second driving power supply line PL2 in accordance with driving of the driving transistor Tdr.

The driving transistor Tdr is connected between a first driving power supply line PL1 and a first electrode (for example, a node electrode) of the organic light emitting diode OLED, And controls the amount of current flowing to the diode (OLED).

The switching transistor Tsw is connected to the gate of the driving transistor Tdr by a data voltage Vdata which is turned on by a scan pulse supplied to the scan control line SCL and supplied to the data line DL To the second node n2.

The sensing transistor Tss is turned on by a control signal supplied to the sensing control line SSL to supply the initial voltage Vini to the third node.

The emission transistor Tem is turned on by the emission signal EM supplied to the emission signal line and supplies a first driving voltage Vdd supplied to the first driving power supply line PL1 to the first node n1.

The first capacitor C1 senses a threshold voltage of the driving transistor during a threshold voltage sensing period and stores a data voltage during a video output period.

The second capacitor C2 increases the efficiency of the data voltage during the video output period and improves the holding characteristic during the emission period.

The lower protective metal BSM is formed below the driving transistor Tdr and the switching transistor Tsw of the pixel P and is formed by a laser and light externally supplied from the driving transistor Tdr, Thereby preventing the element characteristics of the switching transistor Tsw and the sensing transistor Tss, for example, the threshold voltage from fluctuating.

In addition, the lower protective metal may function to prevent the transistor TFT from being physically damaged during the process of removing the glass substrate during the manufacturing process of the flexible organic light emitting display panel.

That is, the lower protective metal prevents the threshold voltage of the transistor from fluctuating for each pixel, thereby preventing a luminance unevenness between pixels.

The emission transistor (Tem) may or may not include a lower protective metal. For example, the emission transistor Tem is for controlling the light emitting period of the organic light emitting diode. In this case, even if the characteristic of the emission transistor is changed by a laser, light, or the like, if the performance change of the emission transistor is substantially not large, a lower protective metal may not be provided under the emission transistor.

In other words, a lower protective metal may be formed in an active lower portion of all transistors applied to the flexible organic light emitting display panel according to the present invention.

For example, a lower protective metal is essentially formed in an active lower portion of the driving transistor, and a lower protective metal may be formed in an active lower portion of the remaining transistors. For example, even if device characteristics such as a threshold voltage are changed due to light or back channel phenomenon introduced from the outside, such as the emission transistor, the switching transistor, or the sensing transistor, Insensitive Therefore, if the device characteristics are determined to affect the characteristics of the organic light emitting display panel, a lower protective metal may be formed under the transistors even though the lower protective metal may not be formed under the transistors. .

The lower protective metal corresponding to the driving transistor Tdr may be connected to either one of the electrodes of the driving transistor or to other electrodes to generate a capacitance increasing effect.

The lower protective metal corresponding to the active state of the transistors other than the driving transistor Tdr such as the switching transistor Tsw or the emission transistor Tem is formed in the lower substrate Or may not be formed.

The lower protective metal may be formed not only on the transistors formed on the pixel but also on the active lower side of various kinds of transistors formed in the non-display area of the flexible organic light emitting display panel.

For example, when the gate driver 200 is formed in the non-display region using a gate-in-panel (GIP) scheme, the gate driver 200 is formed in an active lower portion of various transistors constituting the gate driver 200, A metal may be formed.

In the pad portion of the non-display region, various transistors for inspection of an auto-probe (AP) may be formed, an electrostatic discharge (ESD) circuit may be formed, and a mux may be formed . In this case, the lower protective metal may also be formed in the active lower portion of the transistors forming the components.

When the lower protective metal corresponding to the switching transistor is formed on the lower substrate, the lower protective metal may be floated or connected to one of the electrodes formed on the lower substrate. In the latter case, the lower protective metal may be connected to one of the electrodes constituting the switching transistor corresponding to the lower protective metal.

For example, the lower protection metal corresponding to the switching transistor Tsw may be floating. However, the switching transistor Tsw may also be electrically connected to any one of the metals formed on the lower substrate, in particular, to the gate of the switching transistor Tsw.

In addition, when the lower protective metal is formed in an active lower portion of the transistors forming the various elements formed in the non-display region, the lower protective metal may be floated, or any one Or may be connected to an electrode. In the latter case, the lower protective metal may be connected to one of the electrodes constituting the switching transistor corresponding to the lower protective metal.

Further, the lower protective metals formed for each transistor may be formed in the same layer, but may be formed in different layers. In addition, the lower protective metals may be formed of the same material or different materials. For example, the lower protective metal may be formed of the same material as the gate constituting the transistors, for example, molybdenum (Mo).

Since the lower protective metal layer, which is not connected to any one of the lower protective metals and is formed in a floating state, is used particularly for the purpose of shielding light from the outside, a light shield (L / S: Light Shield) is also called.

FIG. 5A is a cross-sectional view showing a driving transistor of one pixel of a flexible organic light emitting display panel according to a first embodiment of the present invention, FIG. 5B is a cross-sectional view of a switching transistor of one pixel of a flexible organic light emitting display panel according to the present invention, Sectional view.

4, 5A and 5B, a flexible organic light emitting display panel according to the present invention includes a lower substrate 10 formed of plastic, and a buffer 11 formed on the lower substrate 10 . The flexible organic light emitting display panel may include a first active layer 13 which is insulated from the first lower protective metal layer 11a of the buffer layer 11 and overlaps the first lower protective layer 11a And a switching transistor Tsw formed in the buffer 11 and driven according to a scan signal supplied through a gate line GL formed on the lower substrate 10. The flexible organic light emitting display panel further includes a second active layer 23 which is insulated from the second lower protective metal layer 11b constituting the buffer 11 and overlaps with the second lower protective metal layer 11b A driving transistor Tdr which is formed in the buffer 11 and is driven according to a data voltage Vdata supplied through the switching transistor Tsw from a data line DL formed on the lower substrate 10, ). The flexible organic light emitting display panel may further include a planarization layer 42 formed on the switching transistor Tsw and the driving transistor Tdr and a second conductive layer 42 formed on the planarization layer 42, And an organic light emitting diode (E) connected to the electrode.

The lower substrate 10 is formed of plastic on an auxiliary substrate (not shown) made up of a base substrate (not shown) and a sacrificial layer (not shown).

The buffer 11 includes a multi-buffer 11c formed on the lower substrate 10, first and second lower protective metals 11a and 11b formed on the multi-buffer 11c, 1 and an active buffer 11d formed on the second lower protective metal 11a, 11b. The buffer 11 is formed on the lower substrate 10 such that the first and second lower protective metals 11a and 11b and the first and second lower protective metals 11a and 11b, A multi-buffer 11c formed on the multi-buffer 11b, and an active buffer 11d formed on the multi-buffer 11c.

Here, the multi-buffer 11c performs an encapsulation function. That is, since the plastic substrate is used for the lower substrate 10, the multi-buffer 11c can be used to prevent penetration of moisture or the like. Thus, the multi-buffer (11c) may be formed of an inorganic material such as organic materials or Al ₂ O ₃ and SiO ₂ such as a resin.

The active buffer 11d serves to protect the active of the transistor, and functions to block a defect introduced from the lower substrate 10. [ The active buffer 11d may be formed of a-Si or the like.

In addition, the buffer 11 may include the first and second lower protective metals 11a and 11b and a plurality of buffer layers, and the first and second lower protective metals and the plurality May be formed in various structures.

A first and a second active 13 and 23, a gate insulating film 16, a gate 20, an interlayer insulating film 17, and a first driving electrode 33 are formed on the buffer 11 of the OLED display panel. A driving transistor Tdr and a switching transistor Tsw each including a second driving electrode (not shown) are formed.

A protective film 40 and a planarizing film 42 are sequentially formed on the driving transistor Tdr and the switching transistor Tsw of the OLED display panel.

An organic light emitting diode E electrically connected to the first driving electrode 33 of the driving transistor Tdr is formed on the planarization layer 42.

The first lower protective metal 11a is floating and the second lower protective metal 11b is electrically connected to any one of the metals formed on the lower substrate 10.

In other words, the first lower protective metal 11a corresponding to the switching transistor Tsw is floating. However, the first lower protective metal layer 11a may be electrically connected to any one of the metals formed on the lower substrate 10, in particular, to the gate of the switching transistor Tsw.

In the organic light emitting display panel according to the first embodiment of the present invention, the second lower protective metal 11b is electrically connected to the organic light emitting diode via the first driving electrode 33 of the driving transistor Tdr, 1 electrode 47, as shown in FIG.

The lower substrate 10 is sealed with an upper substrate (not shown) in order to penetrate the moisture and protect the organic light emitting diode E from the outside.

The organic light emitting display panel according to the present invention may further include a sensing transistor Tss for sensing a threshold voltage Vth of the driving transistor Tdr and a sensing transistor Tss for sensing the emission period of the organic light emitting diode E. And may further include a transistor Tem. In this case, the buffer 11 is formed with a third lower protection metal (not shown) which is insulated from a third active (not shown) constituting the sensing transistor Tss and overlapped with the third active (not shown) .

The cross section of the sensing transistor Tss and the emission transistor Tem is the same as that of the switching transistor Tsw shown in Fig. 5B.

6 is a cross-sectional view illustrating a driving transistor of one pixel of an organic light emitting display panel according to a second embodiment of the present invention. The second lower protective metal 11b applied to the second embodiment of the present invention is connected to the driving transistor Tdr through the connection electrode 21 formed in the layer in which the gate 20 of the driving transistor Tdr is formed, Tdr and the first electrode 47 of the organic light emitting diode.

A cross section of the driving transistor of the organic light emitting display panel according to the second embodiment of the present invention is the same as that of the driving transistor of the OLED display panel according to the first embodiment of the present invention shown in FIG. Section. In other words, the organic light emitting display panel according to the second embodiment of the present invention is different from the organic light emitting display panel according to the first embodiment of the present invention except for the connection structure of the second lower protective metal 11b and the metal line. .

Therefore, the same or similar contents as those described with reference to FIG. 5A will be omitted or briefly described below.

5B is a cross-sectional view illustrating a switching transistor of one pixel of the OLED display panel according to the second embodiment of the present invention. Therefore, the description of the switching transistor Tsw applied to the organic light emitting display panel according to the second embodiment of the present invention is omitted or briefly described.

The buffer 11 applied to the second embodiment of the present invention may be configured to include a multi-buffer 11c formed on the lower substrate 10, a second lower protective metal (not shown) formed on the multi- And an active buffer 11d formed on the second lower protective metal 11b. The buffer 11 may include a multi-buffer 11c formed on the second lower protective metal 11b and the second lower protective metal 11b formed on the lower substrate 10, And an active buffer 11d formed on the multi-buffer 11c.

6, the second active 23, the gate insulating film 16, the gate 20, the interlayer insulating film 17, and the first driving electrode 17 are formed on the buffer 11 of the OLED display panel. A driving transistor Tdr including a first driving electrode 33 and a second driving electrode is formed.

The second lower protective metal 11b is electrically connected to the first electrode 47 of the organic light emitting diode through the connection electrode 21 formed in the gate layer in which the gate 20 constituting the driving transistor Tdr is formed. Lt; / RTI >

A planarization layer 42 including a protection layer 40 is formed on the driving transistor Tdr of the OLED display panel.

An organic light emitting diode E is electrically connected to the first driving electrode 33 of the driving transistor Tdr on the planarization layer 42.

The lower substrate 10 on which the organic light emitting diodes E are formed is bonded to an upper substrate for encapsulation.

A protective film 40 and a planarizing film 42 are sequentially formed on the driving transistor Tdr of the OLED display panel.

An organic light emitting diode E is electrically connected to the first driving electrode 33 of the driving transistor Tdr on the planarization layer 42.

The lower substrate 10 is sealed with an upper substrate in order to penetrate moisture and protect the organic light emitting diode E from the outside.

One pixel P of the organic light emitting display panel according to the second embodiment of the present invention includes a sensing transistor Tss for sensing a threshold voltage Vth of the driving transistor Tdr, (Em) for controlling the light emission period of the pixel (E). The buffer 11 is formed with a third lower protection metal (not shown) which is insulated from a third active (not shown) constituting the emission transistor (Tem) and overlapped with the third active (not shown) It is possible. The cross section of the sensing transistor Tss and the emission transistor Tem is the same as that of the switching transistor Tsw shown in Fig. 5B.

In the second embodiment of the present invention as described above, the second lower protective metal 11b is electrically connected to the first electrode 47 of the organic light emitting diode through the connection electrode 21 formed on the gate- ), It can be manufactured using the same process as the third embodiment described below.

7 is a cross-sectional view illustrating a driving transistor of one pixel of an organic light emitting display panel according to a third embodiment of the present invention. The second lower protective metal according to the third embodiment of the present invention is electrically connected to a gate constituting the driving transistor. Except for the above, the driving transistor of the OLED display panel according to the third embodiment of the present invention is the same as that of FIG. 5A. Therefore, the same or similar contents as those described with reference to FIG. 5A will be omitted or briefly described below.

5 is a cross-sectional view illustrating a switching transistor of an OLED display panel according to a third embodiment of the present invention. Therefore, the description of the switching transistor applied to the OLED display panel according to the second embodiment of the present invention is omitted or briefly described.

7, one pixel P of the OLED display panel according to the third embodiment of the present invention includes a lower substrate 10 formed of plastic, a buffer 11 formed on the lower substrate 10, And a first active 13 which is insulated from the first lower protective metal 11a constituting the buffer 11 and overlaps with the first lower protective metal 11a, A switching transistor Tsw driven according to a scan signal supplied through a gate line GL formed on the lower substrate 10, a second lower protection metal 11b constituting the buffer 11, And a second active (23) which is insulated and overlapped with the second lower protective metal (11b), and is formed in the buffer (11), from a data line (DL) formed on the lower substrate, A driving transistor Tdr driven according to the data voltage Vdata supplied through the driving transistor Tsw, The flat film to be formed on the transistor (Tdr), (42) and formed on the flat film 42, an organic light emitting diode (E) is connected to the first driving electrode 33 of the driving transistor.

The buffer 11 includes a multi-buffer 11c formed on the lower substrate 10, a second lower protective metal 11b formed on the multi-buffer 11c, And an active buffer 11d formed on the first and second electrodes 11a and 11b. However, the buffer 11 is not limited to the multi-buffer 11c formed on the second lower protective metal 11b and the second lower protective metal 11b formed on the lower substrate 10, And an active buffer 11d formed on the multi-buffer 11c.

A gate 20, an interlayer insulating film 17, a first driving electrode 33, and a second driving electrode are formed on the buffer 11 of the OLED display panel The driving transistor Tdr is formed.

The second lower protective metal 11b is electrically connected to the gate 20 constituting the driving transistor Tdr.

Therefore, the potential of the second lower protective metal 11b can be kept constant, and thus the change in characteristics of the elements around the second lower protective metal 11b can be reduced.

Therefore, when driving the organic light emitting display panel, the second lower protective metal 11b is kept at the same voltage as the gate 20. [ As a result, the second lower protective metal 11b is not affected by the external voltage and is not affected by the back channel phenomenon caused by the lower substrate 10 and the sacrificial layer (not shown) The shift of the threshold voltage Vth of the driving transistor Tdr can be prevented.

Since the second lower protective metal layer 11b is located under the second active layer 23, the lower lower protective metal layer 11b can be separated from the lower substrate 10 by the laser beam irradiated in the process of separating the auxiliary substrate (not shown) The second active 23 of the driving transistor Tdr formed on the substrate 10 can be prevented from being damaged.

One pixel P of the organic light emitting display panel according to the third embodiment of the present invention includes a sensing transistor Tss for sensing a threshold voltage Vth of the driving transistor Tdr, (Em) for controlling the light emitting period of the pixel (E). At this time, the buffer 11 is formed with a third lower protection metal (not shown) which is insulated from a third active (not shown) constituting the emission transistor Tsw and overlaps with the third active (not shown) . The cross section of the sensing transistor Tss and the emission transistor Tem is the same as that of the switching transistor Tsw shown in Fig.

Also, as described above, the lower protection metal corresponding to the switching transistor or the lower protection metal corresponding to the emission transistor may be floating, but may be connected to the gate of the switching transistor or the gate of the emission transistor, respectively It is possible.

According to the third embodiment of the present invention as described above, it is easy to secure the storage capacitance.

Hereinafter, a method of manufacturing a flexible organic light emitting display panel according to the present invention will be described with reference to FIGS. 4 to 8E.

8A to 8E are cross-sectional views illustrating a method of fabricating a flexible organic light emitting display panel according to the present invention, and show cross sections of the driving transistor Tdr. Particularly, FIGS. 8A to 8E show a method of manufacturing the flexible organic light emitting display panel according to the first embodiment of the present invention. However, the methods described below can be applied to the fabrication of the flexible organic light emitting display panel according to the second embodiment of the present invention and the third embodiment of the present invention.

8A to 8E, a flexible organic light emitting display panel according to the present invention includes a step of forming a flexible lower substrate 10 on an auxiliary substrate A, Forming a buffer 11 including a protective metal (not shown) and a second lower protective metal 11b on the buffer 11; A switching transistor Tsw including a first active (not shown) which overlaps with the first lower protective metal 11b and a second active metal (not shown) which is insulated from the second lower protective metal 11b and overlaps with the second lower protective metal 11b. Forming a driving transistor Tdr including the driving transistor Tdr on the top surface of the driving transistor Tdr, forming a flat film 42 on the top of the driving transistor Tdr, The first driving electrode 33 of the driving transistor Tdr driven according to the data voltage supplied through the first electrode Is prepared by performing the steps and the laser release process of forming the organic light emitting diode (E) is connected to the term includes the step of separating the auxiliary substrate (A) in the lower substrate 10.

8A, in the step of forming the flexible lower substrate 10 on the auxiliary substrate A, after the sacrifice layer 85 is formed on the glass substrate 80, The lower substrate 10 which is flexible on the substrate 85 is formed. The lower substrate 10 may be formed of a material such as polyethersulphone (PES), polyacrylate (PAR), polyetherimide (PEI), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), Polyphenylene Sulfide (PPS), Polyallylate, Polyimide, Polycarbonate (PC), Cellulose Triacetate (TAC) and Cellulose Acetate Propionate: CAP).

The lower substrate 10 may be formed, for example, by a spin coating method. In more detail, after the liquid material containing any one of the above-mentioned materials is placed on the sacrifice layer 85, the glass substrate 80 may be rotated at a high speed to form a thin flexible substrate having excellent thickness uniformity.

In addition, the lower substrate 10 may be formed by a roll coating method or a slit coating method. However, the two methods have a disadvantage in that the thickness uniformity is lower than the spin coating method, Is relatively high.

Next, as shown in FIG. 8B, a buffer 11 including a first lower protective metal (not shown) and a second lower protective metal 11b is formed on the lower substrate 10. The buffer layer 11 includes a multi-buffer layer 11c formed on the first substrate, a first lower protection metal (not shown) and a second lower protection metal 11b formed on the multi-buffer layer 11c, And an active buffer layer 11d formed on the first lower protective metal and the second lower protective metal 11b. However, the present invention is not limited thereto, and the buffer 11 may be formed on the lower substrate 10 by using the first lower protective metal (not shown), the second lower protective metal 11b, A multi-buffer 11c formed on the second lower protective metal 11b, and an active buffer 11d formed on the multi-buffer 11c. In addition, the buffer 11 may have a variety of structures using the first lower protective metal (not shown), the second lower protective metal 11b, and a plurality of buffer layers.

Next, as shown in FIG. 8C, a switching transistor including a switching transistor including a first active, which is insulated from the first lower protective metal and overlaps with the first lower protective metal, and a switching transistor which is insulated from the second lower protective metal, A driving transistor Tdr including a second active 23 which overlaps with the second lower protective metal 11b is formed.

The step of forming the driving transistor Tdr may include forming the second active 23 on the buffer 11, forming a gate insulating film 16 on the second active 23, Forming a gate 20 on the gate insulating film 16, forming an interlayer insulating film 17 on the gate 20, forming the second active layer 23 on the interlayer insulating film 17, A first contact hole 61 for exposing the first driving electrode 33 connected to the first lower protective metal 11b and a second contact hole 62 for exposing the second lower protective metal 11b, And forming the first driving electrode (33) and the second driving electrode on the insulating film (17).

The second lower protective metal layer 11b may be formed of a metal forming the driving transistor Tdr or metals forming the driving transistor Tdr or metals forming the organic light emitting diode OLED, And is connected to any one of the metals for supplying power necessary for light emission of the organic light emitting diode (OLED).

The step of forming the switching transistor Tsw includes the steps of forming the first active 13 on the buffer 11, forming a gate insulating film 16 on the first active 13, Forming a gate 20 on the gate insulating film 16, forming an interlayer insulating film 17 on the gate 20, forming the switching transistor Tsw on the interlayer insulating film 17, And forming a first driving electrode 33 and a second driving electrode (not shown).

The second lower protective metal 11b of the driving transistor Tdr is connected to the first driving electrode 33 of the driving transistor Tdr through the second contact hole 62. [ However, the first lower protective metal 11a of the switching transistor Tsw is floating.

The method for manufacturing an organic light emitting display panel according to the present invention is characterized in that the buffer 11 is formed on the buffer 11 so as to be insulated from a third lower protective metal (not shown) A step of forming a sensing transistor Tss for sensing the threshold voltage of the driving transistor Tdr including a triple active (not shown), and controlling the light emitting period of the organic light emitting diode And forming an emission transistor (Tem) for forming an emission region.

Next, as shown in FIG. 8D, a protective film 40 and a flat film 42 are sequentially formed on the driving transistor Tdr. An organic light emitting diode E electrically connected to the first driving electrode 33 of the driving transistor Tdr is formed on the planarization layer 42.

At this time, although not shown, the protective film 40 and the planarization film 42 are sequentially formed on the upper end of the switching transistor Tsw.

Finally, as shown in FIG. 8E, the auxiliary substrate A is separated from the lower substrate 10 by performing a laser-releasing process.

As described above, the method for fabricating an organic light emitting display panel according to the second and third embodiments of the present invention is the same as the method for manufacturing the organic light emitting display panel except for the method of connecting the second lower protective metal 11b to one metal line Is the same as the method of manufacturing the organic light emitting display panel according to the first embodiment of the present invention. Therefore, a method for fabricating an organic light emitting display panel according to the second and third embodiments of the present invention will be briefly described below.

The method of fabricating an organic light emitting display panel according to the second embodiment includes forming a flexible lower substrate 10 on an auxiliary substrate A and forming a first lower protective metal 11a on the lower substrate 10, Forming a buffer 11 including a first lower protective metal 11b and a second lower protective metal 11b on the buffer 11, And a second active 23 that is insulated from the second lower protective metal 11b and overlaps with the second lower protective metal 11b. The switching transistor Tsw includes a first active (not shown) Forming a driving transistor Tdr on the top surface of the driving transistor Tdr and forming a flat layer 42 on the top of the driving transistor Tdr; Which is electrically connected to the first driving electrode 33 of the driving transistor Tdr, Performing step and the laser release process of forming a light emitting diode (E) is produced by including the step of separating the auxiliary substrate (A) in the lower substrate 10.

In particular, in the method of manufacturing an OLED display panel according to the second embodiment of the present invention, the second active layer 23 is formed on the buffer layer 11, and the gate insulating layer 16 A contact hole 21 is formed to expose the second lower protective metal 11b and a connection electrode 21 connected to the second lower protective metal 11b on the gate insulating film 16, An interlayer insulating film 17 is formed on the gate 20 and the connection electrode 21 and the first driving electrode 33 is formed on the interlayer insulating film 17. [ And a second driving electrode are formed.

The method of fabricating an organic light emitting display panel according to the third embodiment includes forming a flexible lower substrate 10 on an auxiliary substrate A and forming a first lower protective metal 11a on the lower substrate 10, Forming a buffer 11 including a first lower protective metal 11b and a second lower protective metal 11b on the buffer 11, And a second active 23 that is insulated from the second lower protective metal 11b and overlaps with the second lower protective metal 11b. The switching transistor Tsw includes a first active (not shown) Forming a driving transistor Tdr on the top surface of the driving transistor Tdr and forming a flat layer 42 on the top of the driving transistor Tdr; Which is electrically connected to the first driving electrode 33 of the driving transistor Tdr, And forming the auxiliary light-emitting diode E and separating the auxiliary substrate A from the lower substrate 10 by performing a laser-releasing process.

In particular, in the method of fabricating an organic light emitting display panel according to the third embodiment of the present invention,

The second active 23 is formed on the buffer 11 and the gate insulating film 16 is formed on the second active 23. The second lower protective metal 11b is exposed, A contact hole is formed in the insulating film 16 and a gate 20 connected to the second lower protective metal 11b through the contact hole is formed on the gate insulating film 16, And a first driving electrode 33 and a second driving electrode of the driving transistor are formed on the interlayer insulating film 17. [

FIGS. 9A to 9C are views illustrating a structure of a transistor applied to a flexible organic light emitting display panel according to an exemplary embodiment of the present invention, and illustrate the sizes of a gate (gate) and an active (ACT). Here, (a) of each drawing is a plan view of the transistor, and (b) is a cross-sectional view taken along the line X-X 'shown in (a).

For example, referring to FIGS. 9A to 9C, an active buffer A / B is formed between the lower protective metal BSM and the ACT, and the source electrode S And a drain electrode D are connected to the gate electrode G. A gate insulating film GI is formed on the active ACT and a gate GATE is formed on the gate insulating film GI.

First, the width of the lower protective metal BSM may be greater than the width of the gate GATE, as shown in FIGS. 9A and 9B. For example, if the width of the gate (GATE) is 20 microns, the width of the lower protective metal (BSM) may be 22 microns. In this case, the end of the lower protective metal (BSM) It can be protruded by the same length from the end.

Next, the width of the lower protective metal BSM may be formed to be smaller than the width of the gate, as shown in Figs. 9 (a) and 9 (b). For example, in the case of 20 [micro] m width of the gate, the width of the lower protective metal BSM may be 18 [micro] m, in which case the end of the gate is protruded by the same length from the end of the lower protective metal .

Finally, the width of the lower protective metal (BSM) may be asymmetrically formed with the gate, as shown in Figures 9 (a) and 9 (b). For example, the lower protection metal BSM may cover one end of the gate but may not cover the other end. In other words, the lower protective metal may be formed in a shape biased toward one side of the gate.

The present invention described above is briefly summarized as follows.

First, in the present invention, since the second lower protective metal (BSM) is formed under the driving transistor of the plastic organic light emitting display panel, the following effects can be generated, Can be secured.

First, the active area of the organic light emitting display panel can be protected.

Secondly, when the laser is released, the damage to the thin film transistor can be prevented.

Third, through the formation of a capacitance between the active and the second lower protective metal, the design of the organic light emitting display panel of high resolution can be made. Fourth, when the device is driven, device variations due to thermal damage on the lower plastic substrate, AB, and MB can be suppressed.

Fifth, since the back channel phenomenon in the plastic substrate and the sacrifice layer causes the sacrifice layer to have a negative charge (< 0 V), the threshold voltage variation (Vth shift) .

Sixth, the device structure according to the present invention is easy to secure a storage cap, and in the device structure according to the present invention, an additional capacitor can be formed in the active-second lower protective metal.

Seventh, by using the second lower protective metal as the same electrode as the gate of the thin film transistor, a double gate effect can be expected.

Next, the second lower protective metal may be disposed between any two layers of the active buffer when the active buffer is fabricated as double or triple. In addition, the second lower protective metal may be disposed between any two layers of the multi-buffer. Also, the second lower protective metal may be used as a storage capacitor in a pixel, or may be used as a wiring of other electrodes.

Next, since the voltage of the switching transistor continuously varies, the first lower protective metal is not electrically connected to a specific metal but is formed in a floating state. Thus, the following effects can be expected through the formed first lower protective metal.

First, changes in the characteristics of the thin film transistor, which are caused by light during the module process of the plastic organic light emitting display, can be prevented.

Second, a change in characteristics of the thin film transistor, which is generated when light is applied to the channel region of the switching transistor, can be prevented.

Thirdly, the mura that can be caused by the characteristic change of the switching transistor due to the light introduced from the outside can be suppressed.

fourth. After fabricating the flexible organic light emitting display panel product, device variations due to light exposed during storage and movement can be prevented.

Fifth, after fabricating a flexible organic light emitting display panel product, device variations due to light generated in the system can be prevented.

Lastly, in addition to the first, second and third lower protective metals, various kinds of transistors formed in each pixel of the organic light emitting display panel, for example, compensating transistors, A protective metal may be formed.

10 is a plan view showing a driving transistor of one pixel of a flexible organic light emitting display panel according to a fourth embodiment of the present invention, and FIG. 11 is a cross-sectional view of the driving transistor shown in FIG. 10 cut along the line Y-Y ' Fig.

A low temperature polysilicon (LTPS) transistor using low temperature polysilicon (LTPS) is used for the flexible organic light emitting display panel according to the fourth embodiment of the present invention.

The low temperature polysilicon (LTPS) transistor is suitable for a high-resolution display device requiring a high response speed because of high charge mobility.

In the low temperature polysilicon transistor, a gate is generally disposed at the top of the active. In this case, there is a high possibility that an off-current occurs. Thus, the low-temperature polysilicon transistor is fabricated using two gate terminals 20a and 20b and two active terminals AT1 and AT2, as shown in Fig.

For example, as shown in FIGS. 10 and 11, a flexible organic light emitting display panel according to a fourth embodiment of the present invention includes a lower substrate 10, a buffer 11 formed on the lower substrate 10 ), An active (ACT) insulated from a lower protection metal (BSM) constituting the buffer (11) and superimposed with the lower protection metal (BSM), a transistor formed in the buffer And an organic light emitting diode (not shown) formed on the flat film (not shown) and the flat film (not shown) and driven by the transistor to output light.

The configuration and function of the flat film (not shown) and the organic light emitting diode (not shown) are the same as those of the first embodiment to the third embodiment, and a detailed description thereof will be omitted.

The fourth embodiment of the present invention differs from the first to third embodiments in the structure of the transistors.

The transistor applied to the fourth embodiment of the present invention may be the switching transistor Tsw or the driving transistor Tdr described in the first to third embodiments, A switching transistor and a transistor other than the driving transistor.

The transistor applied to the fourth embodiment of the present invention has a first gate terminal 20a and a second gate terminal 20b separated from one gate connection line GCL as shown in Figs. 10 and 11, ). Therefore, the first gate terminal 20a and the second gate terminal 20b are electrically connected to each other.

The active ACT includes a first active terminal AT1 overlapping the first gate terminal 20a and a second active terminal AT2 overlapping the second gate terminal 20b.

The first active terminal AT1 and the second active terminal AT2 are connected to each other.

In this case, the lower protective metal BSM may be formed to overlap both the first active terminal AT1 and the second active terminal AT2, as shown in FIGS.

The first active terminal AT1 and the second active terminal AT2 may be connected to a drain electrode or a source electrode, respectively. In Fig. 10, the drain electrode and the source electrode are shown with reference numerals SD1 and SD2.

FIG. 12 is a plan view showing a driving transistor of one pixel of a flexible organic light emitting display panel according to a fifth embodiment of the present invention. FIG. 13 is a cross-sectional view taken along line Y-Y ' Fig. FIG. 14 is a graph showing an example of variation of characteristics with and without a lower protective metal. 14 (a) shows the characteristics of the transistor without the lower protective metal, and FIG. 14 (b) shows the characteristics of the lower protection metal terminals (C) shows the characteristics of the transistors formed such that BSM1 and BSM2 overlap each other. Fig. 12 (c) shows the characteristics of the transistors, in which only one of the two active terminals AT1 and AT2, (BSM2) are overlapped with each other.

As described above, the transistor used in the fourth embodiment of the present invention is a transistor using low-temperature polysilicon (LTPS). In this case, the transistor has two gate terminals 20a and 20b and two active Terminals AT1 and AT2.

As shown in FIGS. 10 and 11, the buffer 11 includes a first lower protective metal terminal BSM1 and a second lower protective metal terminal BSM2 overlapping the two active terminals AT1 and AT2. Is formed.

If the gap between the two gate terminals 20a and 20b is, for example, 4 占 퐉, the gap between the first lower protective metal terminal BSM1 and the second lower protective metal terminal BSM2 is Lt; / RTI &gt;

In this case, since the interval between the first lower protective metal terminal BSM1 and the second lower protective metal terminal BSM2 is narrow, the first lower protective metal terminal BSM1 and the second lower protective metal terminal BSM2, BSM2) may be difficult to design and implement.

In addition, the parasitic capacitance between the first lower protective metal terminal BSM1 and the second lower protective metal terminal BSM2 and the gate terminals 20a and 20b is increased, so that the characteristics of the transistor can be changed .

The fifth embodiment of the present invention is different from the fourth embodiment in that the gap between the first lower protective metal terminal BSM1 and the second lower protective metal terminal BSM2 is small and the parasitic capacitance is considered do.

For example, as shown in FIGS. 12 and 13, the organic light emitting display panel according to the fifth embodiment of the present invention includes a lower substrate 10, a buffer 11 formed on the lower substrate 10, (ACT) insulated from a lower protection metal (BSM1) constituting the buffer (11) and overlapping the lower protection metal (BSM1), the transistor formed in the buffer, the flatness And an organic light emitting diode (not shown) formed on the flat film (not shown) and driven by the transistor to output light.

The organic light emitting display panel according to the fifth embodiment of the present invention differs from the fourth embodiment in that the lower protection metal includes one lower protection metal terminal BSM2. Therefore, in the description of the fifth embodiment, the lower protective metal and the lower protective metal terminal are used in the same sense and refer to BSM2 shown in Figs. 12 and 13.

For example, the transistor includes a first gate terminal 20a and a second gate terminal 20b separated from one gate connection line GCL, and the active (ACT) (AT1) overlapping the first gate terminal (20a) and a second active terminal (AT2) overlapping the second gate terminal (20b), wherein the first active terminal (AT1) and the second active terminal (AT2) are connected to each other, and the lower protective metal (BSM) overlaps only either the first active terminal or the second active terminal.

Particularly, FIGS. 12 and 13 show an organic light emitting display panel in which a lower protective metal BSM2 is formed in a region overlapping the second active terminal AT2.

In this case, the lower protective metal BSM is formed in the buffer 11, the first active terminal AT1 and the second active terminal AT2 are stacked in the buffer 11, The active terminal AT1 and the second active terminal AT2 are covered with a gate insulating film 16 and the first gate terminal 20a overlapped with the first active terminal AT1 is formed in the gate insulating film 16. [ And the second gate terminal 20b overlapping the second active terminal AT2.

Since the organic light emitting display panel according to the fifth embodiment of the present invention has only one of the first lower protective metal terminal BSM1 and the second lower protective metal terminal BSM2 described in the fourth embodiment , The design and formation of the lower protective metal can be facilitated.

Since the area of the lower protective metal constituted by one lower protective metal terminal BSM2 is smaller than the area of the lower protective metal composed of the two lower protective metal terminals BSM1 and BSM2, The parasitic capacitance between the lower protective metal terminal and the gate terminals is reduced. Therefore, the characteristics of the transistor are not greatly changed.

As a result of the simulation and the actual measurement, the characteristics of the organic light emitting display panel according to the fifth embodiment are superior to those of the organic light emitting display panel having no lower protection metal. In the fourth embodiment, , BSM2) having the lower shielding metal. That is, as in the fifth embodiment, the reliability of the transistor provided in the organic light emitting display panel having the lower protective metal constituted by one lower protective metal terminal BSM2 can be improved, as in the fourth embodiment, Has the same level of reliability as that of the transistor provided in the organic light emitting display panel having the lower protective metal (BSM) composed of the terminals BSM1 and BSM2.

More specifically, the lower protective metal is formed to secure the reliability of the transistor, and FIG. 14 is a graph showing a cure change of the transistor when a positive voltage is applied at a high temperature . In the graph shown in Fig. 14, the larger the variation of the graph, the less the characteristics of the transistor.

In this case, the variation (see (c)) of the graph of the transistor applied to the OLED display panel according to the fifth embodiment of the present invention is smaller than the variation (see (a)) of the graph of the transistor having no lower protective metal (B) of the graph of the transistor applied to the organic light emitting display panel according to the fourth embodiment of the present invention.

Therefore, according to the fifth embodiment, it is possible to manufacture an organic light emitting display panel which is excellent in reliability of the transistor and easy to manufacture and design.

The method of manufacturing the organic light emitting display panel according to the fourth or fifth embodiment of the present invention is similar to the method of deflecting the organic light emitting display panel according to the first to third embodiments of the present invention. A method of manufacturing the organic light emitting display panel according to the fourth embodiment or the fifth embodiment of the present invention will be briefly summarized as follows.

First, a buffer 11 including a lower protective metal is formed on the lower substrate 10.

Next, on the buffer 11, a transistor including an active (ACT) insulated from the lower protection metal and overlapped with the lower protection metal is formed.

Next, a flat film (not shown) is formed on the top of the transistor.

Finally, an organic light emitting diode (not shown) is formed on the flat film (not shown), which is driven by the transistor and outputs light.

The process of forming the transistor is as follows.

First, in the buffer 11, a first active terminal AT1 and a second active terminal AT2 constituting the active (ACT) are stacked.

Second, the first active terminal AT1 and the second active terminal AT2 are covered with the gate insulating film 16.

A gate (GATE) having a first gate terminal 20a and a second gate terminal 20b overlapping the first active terminal AT1 and the second active terminal AT2 is formed in the gate insulating film 6, Is formed.

In this case, the lower protective metal BSM is formed in the buffer 11 so as to overlap with the first active terminal AT1 and the second active terminal AT2, as shown in FIGS. 10 and 11 . In this case, the lower protective metal BSM includes a first lower protective metal terminal 20a which overlaps with the first active terminal AT1 and a second lower protective metal terminal 20a which overlaps with the second active terminal AT2. 20b. 12 and 13, the lower protective metal BSM is connected to the buffer 11 (only one of the first active terminal AT1 and the second active terminal AT2) As shown in FIG. In this case, the lower protective metal BSM includes a lower protective metal terminal SMB2 which overlaps only either the first active terminal AT1 or the second active terminal AT2.

The buffer 11 may include the multi-buffer 11c and the active buffer 11d in addition to the lower protective metal BSM. The stacking order of the multi-buffer 11c, the active buffer 11d, and the lower protective metal BSM2 may be variously set as described above.

Further, the lower protection metal (BSM) formed in the overlapping manner with the two gate terminals 20a and 20b described in the fourth embodiment of the present invention, or the lower protection metal (BSM) described in the fifth embodiment of the present invention, The lower protective metal BSM2 formed to overlap with only one of the two gate terminals 20a and 20b may be floated with other electrodes as described above, Or may be connected to any one electrode formed on the substrate 10. In the latter case, the lower protection metal (BSM) may be connected to one of the electrodes constituting the transistor corresponding to the lower protection metal (BSM).

100: Panel 110: Pixel
200: gate driver 300: data driver
400: timing controller 10: lower substrate
11: buffer 11a: first lower protective metal
11b: second lower protection metal BSM: lower protection metal
BSM1: first lower protection metal terminal BSM2: second lower protection metal terminal
ACT: active AT1: first active terminal
AT2: second active terminal 20: gate
20a: first gate terminal 20b: second gate terminal

Claims (17)

A lower substrate;
A buffer formed on the lower substrate;
And a second active protective film formed on the buffer, the first active protective film being insulated from a first lower protective metal constituting the buffer and overlapping with the first lower protective metal, A switching transistor driven according to a scan signal;
And a second active layer which is insulated from a second lower protective metal constituting the buffer and overlaps with the second lower protective metal, and is formed in the buffer, and from the data line formed on the lower substrate, A driving transistor driven according to a data voltage supplied through the driving transistor;
A flat film formed on the switching transistor and the driving transistor; And
And an organic light emitting diode (OLED) formed on the planarization layer and having a first electrode connected to a first driving electrode of the driving transistor. The method according to claim 1,
Wherein the first lower protective metal is floated,
And the second lower protective metal is electrically connected to one of the metals formed on the lower substrate. The method according to claim 1,
And the second lower protective metal is electrically connected to the first electrode. The method of claim 3,
Wherein the second lower protective metal is connected to the first electrode through a connection electrode formed in a gate layer in which a gate constituting the driving transistor is formed. The method according to claim 1,
And the second lower protective metal is electrically connected to a gate constituting the driving transistor. The method according to claim 1,
The buffer includes:
A multi-buffer formed on the lower substrate, a first lower protection metal and a second lower protection metal formed on the multi-buffer, and an active portion formed on the first lower protection metal and the second lower protection metal, Buffer, or
A multi-buffer formed on the first lower protective metal and the second lower protective metal, the first lower protective metal and the second lower protective metal formed on the lower substrate, and an active buffer layer formed on the multi- A flexible organic light emitting display panel comprising a buffer. The method according to claim 1,
A sensing transistor for sensing a threshold voltage of the driving transistor; And
Further comprising an emission transistor for controlling an emission period of the organic light emitting diode,
Wherein the buffer is formed with a third lower protective metal which is insulated from a third active constituting the sensing transistor and overlaps with the third active. The method according to claim 1,
Wherein the switching transistor includes a first gate terminal and a second gate terminal separated from one gate connection line,
Wherein the first active includes a first active terminal overlaid on the first gate terminal and a second active terminal overlying the second gate terminal,
Wherein the first active terminal and the second active terminal are connected to each other,
Wherein the first lower protective metal overlaps only either the first active terminal or the second active terminal. The method according to claim 1,
Wherein the driving transistor includes a first gate terminal and a second gate terminal separated from one gate connection line,
The second active includes a first active terminal overlaid on the first gate terminal and a second active terminal overlying the second gate terminal,
Wherein the first active terminal and the second active terminal are connected to each other,
Wherein the second lower protective metal overlaps only either the first active terminal or the second active terminal. The method according to claim 1,
Wherein each of the first active and the second active is made of low-temperature polycrystalline silicon. A lower substrate;
A buffer formed on the lower substrate;
A transistor formed in the buffer, the buffer being insulated from a lower protective metal constituting the buffer and being superimposed on the lower protective metal;
A flat film formed on the transistor; And
And an organic light emitting diode formed on the flat film and driven by the transistor to output light,
The transistor comprising a first gate terminal and a second gate terminal separated from one gate connection line,
The active includes a first active terminal overlaid on the first gate terminal and a second active terminal overlying the second gate terminal,
Wherein the first active terminal and the second active terminal are connected to each other,
Wherein the lower protective metal overlaps only one of the first active terminal and the second active terminal. 12. The method of claim 11,
The first active terminal and the second active terminal are stacked in the buffer,
The first active terminal and the second active terminal are covered with a gate insulating film,
The first gate terminal overlapping the first active terminal and the second gate terminal overlapping the second active terminal are stacked in the gate insulating film. Forming a buffer on the lower substrate comprising a first lower protective metal and a second lower protective metal;
A switching transistor including a first lower protective metal and a first active on the buffer, the switching transistor being insulated from the first lower protective metal and overlapping the first lower protective metal, Forming a driving transistor including a second active;
Forming a flat film on top of the switching transistor and the driving transistor;
And forming an organic light emitting diode having a first electrode electrically connected to a first driving electrode of the driving transistor driven according to a data voltage supplied through the switching transistor on the flat film, A method of manufacturing a display panel. 14. The method of claim 13,
The second lower protective metal layer may be formed of one of metals forming the driving transistor or metals forming the driving transistor, or metals forming the organic light emitting diode, or metals supplying power for emitting light of the organic light emitting diode And connecting the organic light emitting display panel to the organic light emitting display panel. 14. The method of claim 13,
And a third active layer on the buffer, the third active layer being insulated from a third lower protective metal constituting the buffer and overlapping the third lower protective metal layer, and forming a sensing transistor for sensing a threshold voltage of the driving transistor step; And
And forming an emission transistor for controlling the emission period of the organic light emitting diode on the buffer. 14. The method of claim 13,
Wherein forming the switching transistor and the driving transistor comprises:
Depositing in the buffer a first active terminal and a second active terminal constituting the first active and a first active terminal and a second active terminal constituting the second active;
Covering the first active terminals and the second active terminals with a gate insulating film; And
A gate having a first gate terminal and a second gate terminal overlapping the first active terminal and the second active terminal constituting the first active, and a gate having a first gate terminal and a second gate terminal overlapping the first active terminal and the second active terminal, Forming a gate having a first gate terminal and a second gate terminal overlapping the active terminal and the second active terminal,
Wherein the first lower protective metal overlaps only one of the first active terminal and the second active terminal constituting the first active,
Wherein the second lower protective metal is overlapped only with either the first active terminal or the second active terminal constituting the second active. Forming a buffer on the lower substrate comprising a lower protective metal;
Forming a transistor on the buffer, the transistor being insulated from the lower protection metal and being active with the lower protection metal;
Forming a planar film on top of the transistor; And
Forming an organic light emitting diode driven by the transistor and outputting light on the flat film,
Wherein forming the transistor comprises:
Stacking a first active terminal and a second active terminal constituting the active in the buffer;
Covering the first active terminal and the second active terminal with a gate insulating film; And
Forming a gate in the gate insulating film having a first gate terminal and a second gate terminal overlapping the first active terminal and the second active terminal,
Wherein the lower protective metal overlaps only one of the first active terminal and the second active terminal.

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